A Flushing System to Clean up Coastal Lagoons

The stability of coastal lagoons is often precarious. Their ecological balance is easily altered by changes in the surrounding environment, particularly those of nearby urban developments. Common problems include pollution and eutrophication. Since these lagoons are generally connected to the sea by either natural or artificial channels, one way to improve water quality in the lagoon is to increase the input of seawater through these channels, thus flushing out the pollutants and thereby controlling eutrophication. One of the main advantages of the flushing system presented in this paper is that virtually no maintenance is required. From the experiments carried out in the laboratory and on the coast an analytical model was developed to assist in the design of a wave amplifier. The analytical model is in agreement with the results obtained with monochromatic waves in the laboratory. The seawater obtained by such a method could be injected into a coastal lagoon to flush out pollutants and improve water quality. A wave amplifier of this type could also be used to clean out tanks at aquaculture farms on the coast.